| Titre : |
Syndet cleansing bars : the better 'soap' ? |
| Type de document : |
texte imprimé |
| Auteurs : |
Alexander T. Wagner, Auteur ; Torsten Krohn, Auteur |
| Année de publication : |
2019 |
| Article en page(s) : |
p. 111-114 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Catégories : |
Cosmétiques
Lingettes -- Emploi en cosmétologie
Peau -- Soins et hygiène
Produits nettoyants
Savon
Solutions aqueuses (chimie)
Surfactants
|
| Index. décimale : |
668.5 Parfums et cosmétiques |
| Résumé : |
Flashback to the 1930s: "The principal object of the invention is to provide a soap composition which is totally stable in the presence of hard water, strongly alkaline or acid waters, producing no insoluble precipitates whatever".' This fundamental statement was made by Heinrich Bertsch in his patent "Soap Preparation". It proves that already more than 80 years ago proposais were made to overcome a well-known drawback of classical soaps: Precipitation in water. There are two chemical reactions of soaps - the alkali salts of fatty acids - (Fig 1) which cause the precipitates. Both of them "knock-out" typical surfactant properties like cleansing and foaming. Firstly, the reaction of soaps with magnesium and particularly calcium ions in hard water leads to water-insoluble precipitates (lime soap). Lime soap is difficuit to remove from hard surfaces like wash basins. Secondly, even at neutral pH conditions, soaps to a great extent become fatty acids by protonation (Fig 2). Then they are (nearly) water-insoluble. This chemical reaction is the background of the statement given above:' The instability of pure soaps in 'acid waters'. The protonation is directly linked to the creation of an alkaline solution (Fig 2) and leads to a pH of soap solutions of about 9 —11. For cosmetic applications this behaviour is considered the major drawback in using solid soap bars, as the pH of the skin is about 5.0 to 5.5. It is easily understandable that skin cleansing in a non-natural pH-range may stress the skin. Therefore, for cosmetic applications there is a trend for pH-skin neutral products, which protect the skin by not damaging the natural acid layer. In this article we present some Insider'-tricks to create solid cleansing bars with neutral or even skin-neutral pH-values when dissolved in water. |
| Note de contenu : |
- Focus on soaps in aqueous solutions
- Sulfate surfactants : as co-surfactants for 'combo bars'
- Sulfonate surfactants : as soap replacement for 'syndet bars'
- Composition of solid cleansing bars : syndets versus soaps
- Aesthetic aspects
- Tailor-made products
- Amino acid surfactants - carboxylate-based alternatives to soaps ?
- A comeback of solid cleansing bars in Europe ?
- Fig. 1 : Soap (sodium laurate)
- Fig. 2 : Protonation of soaps : creating fatty acids and an alkaline solution (OH-)
- Fig. 3 : Sodium fatty alcohol sulfate
- Fig. 4 : Sulfonate surfactants : disodium alkyl sulfo sucinate and sodium acyl isethionate
- Fig. 5 : Transparent solid cleansing bars
- Fig. 6 : Zschimmer & Schwarz raw material for producing solid cleansing bars
- Fig. 7 : Amino acid-based surfactants : Sodium acyl sarcosinate and sodium acyl glutamate
- Fig. 8 : Zetesap-Types : "exceptionally creamy foam" |
| En ligne : |
https://drive.google.com/file/d/1Q2UHFg-NAgJmheFJggsgOZnMMfJBZjSd/view?usp=drive [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32250 |
in PERSONAL CARE EUROPE > Vol. 13, N° 3 (04/2019) . - p. 111-114
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Syndet cleansing bars : the better 'soap' ? in PERSONAL CARE EUROPE, Vol. 13, N° 3 (04/2019)
